The demonstration of this law presents itself under two distinct forms. In the first place Comte supports his argument by history. This proves indeed that every branch of our knowledge passes in turn through the three states, with never a single retrogression. It is true that much of our knowledge has not yet reached the positive state. But at any rate it is established that up to the present even those sciences which have not yet reached that state have all described the same curve, already described by those that have reached it.
Historical verification would suffice, if necessary, provided it were complete. Comte is not satisfied with it. He claims moreover to deduce the law of the three states from the nature of man. He will thus give a direct demonstration of it. However useful history may appear to him as an instrument of proof, he still wishes to render its verdict intelligible. To reach this end he has recourse to psychology. “We ought,” he says, “carefully to characterise the general motives, drawn from an exact knowledge of human nature, which must have rendered partly inevitable, partly indispensable, the necessary succession of social phenomena, considered directly with respect to the intellectual development which dominates essentially their chief advance.”[15]
In the first place, the human mind could only begin to interpret nature by a philosophy of the theological type. For it is the only one which is spontaneously produced, the only one which does not presuppose another. Man at first conceives all activity on the same plan as his own. In order to understand phenomena, he likens them to his own actions, whose mode of production he thinks he apprehends, because he has the feelings of his own efforts and the consciousness of his own volitions. This anthropomorphic explanation comes so naturally to us that we are always ready to give way to it. Even to-day, if we forget positive discipline for a moment, if we venture to ask for the mode of production of some phenomenon, we immediately dimly imagine an activity more or less like our own. And among the metaphysicians who profess to give an idea of God, the most consistent, according to Comte, are those who make a person of Him.
The spontaneity which characterises the theological mode of thought has been extremely useful. Without it, we do not see how man’s intelligence could have begun to unfold itself. For, in order to form a scientific theory, however modest and fragmentary, of natural phenomena, the mind needs previous observations, while, on the other hand, in default of a theory, or at any rate of a preexisting hypothesis, no scientific observation is possible. Absolute empiricism, says Comte, is barren, and even, strictly speaking, inconceivable. Simple collections of facts, however numerous we may suppose them to be, do not possess by themselves any scientific significance. Such, for instance, would be the case in the meteorological facts, making interminable lists, and filling volumes. They would only become observations if in collecting them the mind tried to put upon them some interpretation, however vague or precise, real or chimerical.
Caught between the two equally imperative necessities of observing in the first place in order to reach “suitable conceptions”, and of conceiving at the same time some theory in order to make coherent observations, the human mind saves itself by the theological mode of thought. For it has no need of previous observations to imagine everywhere in nature activities similar to its own. Once this hypothesis has arisen, observation comes into play, first to confirm it, but soon to oppose it. From that moment the impulse has been given. The evolution of the sciences and of philosophy will be continued through doctrines which will succeed each other in a necessary order.
In the same way, from the moral point of view, a theological philosophy alone could at first inspire weak and ignorant humanity with sufficient courage and confidence to shake off its primitive torpor. To-day, if man knows that phenomena are subject to invariable laws, he also knows that a knowledge of these laws gives him a certain control over nature. But in the days when man could not foresee the power of science, the idea that phenomena obeyed necessary laws would have filled him with despair. It would probably have paralysed him for all exertion. The theological mode of thought was far more encouraging since the phenomena are imagined to be arbitrarily modifiable. Anything may happen. Nothing is impossible, neither is anything necessary. The will of the gods suffices for a thing to happen or not to happen. Directly, man has no power over nature; indirectly he can do everything, provided only that he can propitiate the divinities whose will is law. In this way, it is at the moment when man’s impotence is greatest, that his confidence in his own power is the strongest.
Finally, from a social point of view, theological philosophy was indispensable for human society to subsist and to be developed. For this society does not merely imply sympathy of feeling and union of interests among its members, but first and above all unanimous adhesion to certain beliefs. Without a “certain system of common preliminary opinions” there can be no human society. But, on the other hand, how can we conceive the appearance of such a system, if social life is not organised? Here is a new vicious circle, out of which the theological philosophy alone can release us. It constitutes at first sight a totality of common beliefs. All the members of the society defend them all the more energetically, because with them are bound up their hopes and their fears, for this world, and for the next, if they already believe in it.
At the same time, this theological philosophy determines the formation, in society, of a special class, consecrated to speculative activity. What an immense progress this division between practice and theory must have been, however roughly outlined! Such a division was established as soon as a sacerdotal class began to be distinguished from the rest of the social body. And how slow this progress must have been, when we see even to-day how hard it is for men to accept any innovation which does not seem to carry with it any immediate practical advantage! The sacerdotal class, invested, by the nature of its functions with an authority which was precious for social progress, at the same time enjoyed that leisure which is indispensable for theoretical research. “Without the spontaneous establishment of such a class,” says Comte, “all our activity, thenceforth exclusively practical, would have confined itself to the improvement, very soon checked, of some processes having reference to military or industrial life.”[16] The subsequent division of labour depended upon this initial step. Our savants, our philosophers, our engineers descend from the first priests, sorcerers and rain conjurors.
Thus, given the nature of Man, the theological philosophy was bound to appear spontaneously. This appearance was at the same time “inevitable and indispensable,” in a word, necessary. Immediately begins what one might call the dialectics of the intellectual history of humanity. The theological philosophy has made possible the observation of phenomena. In its turn, this observation introduces the idea of invariable laws into the mind, whereby the theological philosophy begins to be compromised. The time comes when it appears antiquated and pernicious and reason tends to take the place of the imagination in the interpretation of nature. The more evolution advances, the more marked becomes the preference of the human mind for the positive mode of thought, and, in the several orders of the sciences, after a more or less prolonged conflict, this latter ends by obtaining the ascendancy.
As a matter of fact, the theological stage of our knowledge, even when it exercises its greatest dominion, that is to say, at the time nearest to its origin, already contains the germs of its own decomposition. It is never perfectly homogeneous. There are very common phenomena whose regularity man has never failed to recognize, and which he has never conceived as depending upon arbitrary wills. Comte likes to quote a passage from Adam Smith, where that philosopher remarks that in no time and in no country do we find a god of Weight. Moreover, since the existence of society, man must have had some idea of psychological laws since he was obliged to regulate his conduct according to the way in which his fellows thought and acted. Consequently “the elementary germ of positive philosophy is quite as primitive, at bottom, as that of theological philosophy, although it could only be developed very much later.”[17] Not being universal, theological philosophy could only be provisional. The philosophy, that is to say, the method of interpretation of natural phenomena, will alone be final, which will be applicable to all phenomena without exception, from the most simple to the most complicated. For this philosophy alone will realise the unity demanded by the understanding.